code: def test_clustering_directed_small(self):
      plt.close("all")
      g = Graph.Ring(5, directed=True)
      clu = VertexClustering(g, [0] * 5)
      fig, ax = plt.subplots()
      plot(
          clu,
          target=ax,
          mark_groups=True,
          layout=self.layout_small_ring,
      )
  
imports: import os
  import unittest
  from igraph import Graph, plot, VertexClustering, Layout
  from ...utils import overridden_configuration
label_desc: Use image node_id 4 for calling the ClusteringTestRunner obj's underlying member method code with example usage: obj.test_clustering_directed_small() without return types